import Vue from 'vue'
import VueRouter from 'vue-router'
import Login from '@/components/Login'
import Home from '@/components/Home'
import Welcome from '@/components/Welcome'
import User from '@/components/user'

Vue.use(VueRouter)

const routes = [
  {
    path: '/',
    redirect: 'login'
  },
  {
    path: '/login',
    component: Login
  },
  {
    path: '/home',
    component: Home,
    redirect: '/welcome',
    children: [
      {
        path: '/welcome',
        component: Welcome
      },
      {
        path: '/users',
        component: User
      }
    ]
  }
]

const router = new VueRouter({
  routes
})

// 挂载路由导航守卫
router.beforeEach((to, from, next) => {
  // to 将要访问的路径
  // from 代表从哪个路径跳转而来
  // next 是一个函数，表示放行
  // next() 放行， next('/login') 强制跳转到 login
  if (to.path === '/login') {
    return next()
  }
  // 获取token
  const tokenStr = window.sessionStorage.getItem('token')
  if (!tokenStr) {
    return next('/login')
  }
  next()
})

// 解决ElementUI导航栏中的vue-router在3.0版本以上重复点菜单报错问题,element-ui.common.js?5c96:3354 Error: Avoided redundant navigation to current location: "/users
const originalPush = VueRouter.prototype.push
VueRouter.prototype.push = function push (location) {
  return originalPush.call(this, location).catch(err => err)
}

export default router
